On Windows, the Alt key functions as a modifier like the Shift key. To make special characters, hold down the Alt key and type in the numbers from the numeric keypad. Note that on the some small keyboards (e.g. laptop keybaords) the “numeric keypad” is found by pressing the NumLock key and then looking for the keys on your keyboard that double as numeric keypad keys when in NumLock mode.
How to use this chart :
You can use the html name or number codes in an HTML document (i.e. a webpage or an e-mail that uses HTML format.)
For Macintosh: press the keys as shown. for example “shift+option+w” means press down the shift key, the option key, and the w key all at the same time. “option+e E” means press down the option key and the e key at the same time, then press the E key (capital E).

Western european special characters and how to enter them from your keyboard